Worm Composting

I came across an excellent article yesterday evening called Humanure Composting. It not only covers the author’s own personal experimentation in this area (which believe it or not, makes for intriguing reading), but it also offers insightful commentary on the topic of human waste management in general – effectively highlighting how, despite our so-called advancements in modern sanitation, we have in a sense gone backwards.

Here is a great excerpt from the article:

The fundamental (so to speak) error in the way we have thought about human wastes for a couple of centuries is to think of them as waste at all, i.e. as dross or discard, a substance with no value — or a substance with extreme negative value (dirty, pathogenic, icky). The collection of humanure and urine into centralised processing centres to be biocidally or biotically neutralised and then dumped into bodies of water means that we have interrupted the nutrient cycle, turned what should be a circular energy diagram into a linear one. Instead of returning the excess or byproduct of our metabolic function to the soil that produced the food we ate — as every other living creature on Earth does in a healthy biotic system — we have intervened; we “flush away” our own metabolic byproducts and (in modern times) dump them far, far from the fields which fed us. We thus impoverish the soil (by removing nutrients, minerals, elements which are not replaced), and increase the cost of agriculture by having to replace artificially the missing nutrients, etc.

If this is a topic area that even remotely interests you, I highly recommend that you check out the full article: Humanure Composting (on the ‘Feral Scholar’ blog).

This is one of those topics that will almost certainly make some (if not many) readers squeamish. After all, we’ve essentially been programmed to think of our ‘waste’ products as dirty, disgusting, and dangerous – better known as the ’3 Ds of Doo Doo’ (ok, so I just made that up) – so it can require a pretty substantial paradigm shift to wrap our heads around the notion of dealing with our own wastes in any manner other than what is considered the ‘norm’ (i.e. the porcelain genie that makes it magically disappear).

As many readers probably know by now, I’m very passionate about this idea of wastes being ‘misplaced resources’ – hence the Compost Guy motto, ‘turning wastes into resources’. As such, the topic of human waste is certainly a topic of interest (not in any sort of creepy, obsessive way, of course – haha), and something I’ll definitely be writing more about here. Aside from blog posts, I will be putting together a resource page all about composting toilets as well.

Back to the article…

The author was originally inspired to start her own humanure composting experiment after she read Joe Jenkins’ “Humanure Handbook” (incidentally, a book I myself own and plan to write more about here) – but rather than going the thermophilic composting route, she opted for vermicomposting. I’ve heard of numerous examples involving the successful use of composting worms in a compost toilet, so I wasn’t too surprised to learn how well they thrived in her outdoor humanure heaps. Nevertheless, I was in awe of her bravery for trying this out in a small suburban yard (not in a conventional composting toilet, or even a rural property), with neighbours only a short distance away. In fact, she continued with the project for 2 years (likely without anyone suspecting a thing) – clearly a indication that such practices don’t necessarily create a horrific, smelly mess, at least not if done properly.

I’ve been looking forward to someday having my own composting toilet. To me, the idea of flushing it all away (along with countless gallons of clean water) just doesn’t make much sense. I could only imagine what would happen if we (society) put more focus on these materials as nutrient resources. As the author of the article points out herself, it’s pretty crazy that we have such strong feelings about the safety concerns associated with human waste, yet we have zero issues with spraying all sorts of nasty pesticides (and other chemicals) on our properties (among countless other hazards we just don’t take the time to consider).

Anyway, despite my keen interest in all this, it’s not too likely that I’ll be making my own low-tech humanure bucket system (as the author did) anytime soon – it’s enough of a challenge just keeping my wife happy with all the worm bins (and other experiments) in the house!

I wrote about this on the Red Worm Composting blog this morning, but figured it wouldn’t hurt to make mention of it over here as well.

This morning I was pleasantly surprised when a delivery person rang the doorbell, with a cardboard box in hand. I knew it could only be one thing – worm castings, care of the friendly folks at Worm Power (RT Solutions)! Whoohoo!

One of the awesome things about being an active (and I like to think, passionate) blogger in a particular field is that it’s a great way to connect with cool people doing really neat things (like making worm compost for a living!). I’ve written about Worm Power (on the RWC blog – see Worm Power and Worm Power Videos) a couple times over the past few months, and have had quite a few friendly exchanges with them as a result.

These e-mail exchanges eventually led me to inquire about purchasing some worm castings, so that I could test them out for myself. Of course, having multiple worm composting systems (several of which I could literally reach down a touch as I type – well ok, that would make for some awkward typing), I COULD get my hands on some worm castings if I needed to, and I’ve already proven to myself how well the stuff works (via previous experimentation). But when it comes down to it, I’ve always wanted to try out castings produced in a state-of-the-art ‘flow-through reactor’ (pretty well the ultimate in professional worm composting systems).

Long story, short…rather than telling me how much it was going to cost me (as would be expected), they offered to send me a 3 lb tub of castings to play with! (thanks again, guys!) – yet another advantage of having a ‘voice’ in the online composting arena I guess.

Anyway, I can’t wait to start playing with my new tub o’ dirt! It’s going to be a lot of fun. Needless to say, I’ll keep my readers up to date with any fun activities/results worth mentioning (lots of interesting stuff planned, and certainly not just limited to worm castings!).

I received an interesting e-mail query from a reader yesterday and it has inspired me to write a post comparing worm composting with bokashi. You may recall that I’ve previously written about ‘Hot Composting vs Vermicomposting‘, so it only makes sense that I throw bokashi into the mix, now that I’m becoming such a bokashi pro (ha ha)!

Ok, here are some bits and pieces taken from the emails I received from our reader, ‘JBB’ (second blurb is from another email they sent after I replied)

i read some of you articles, and i can’t find a comparison between
bokashi and vermicomposting.
I mean, i want to do home composting (without a garden), but i don’t
know which one to choose between bokashi and vermicomposting.
.
.
.
What makes me ask questions is the article about bokashi composting on
cityfarmer, where it say :
“that stuff does break down very fast in the soil, and that when I dig
in the area a month or two later it is absolutely WRITHING with earthworms.”
So maybe the two process are complementary, and bokashi is just the
start of a complete composting solution, where the worms are needed to
end the process …

This is an excellent question and I’m very glad JBB decided to e-mail me. I’m sure there are a lot of people trying to decide what waste management strategy (or variation thereof) will work best for them.

Let me start by saying that I am a firm believer in the notion that there is no one ‘be all, end all’ strategy out there – especially when we are talking about subjects relating to ‘sustainability’. The more I learn about all these various fascinating ways that ‘wastes’ are converted to resources (composting, vermicomposting, bokashi, aquaponics, recycling etc), the more I believe that they should all play a role, as part of a larger integrated whole.

Dr. John Todd’s various ‘Eco Machines‘ provide an excellent demonstration of this idea. I still remember vividly my first encounter with Dr. Todd’s work – almost certainly one of the turning points in my life in terms of the direction I wanted to head. It was a video I found online (sadly it is nowhere to be found now) that featured a system Dr. Todd set up in Burlington Vermont. It all started with brewery waste which was used to grow gourment Oyster mushrooms. The spent mushroom substrate was then fed to Red Worms, which were in turn used to feed Yellow Perch. Small (edible) shrimp helped to clean up fish waste, which was further assimilated by a wide assortment of plant (edible and ornamental). Multiple marketable ‘products’ were produced – all from a material that is considered a waste product!

It’s funny how the only ‘waste’ happening is the misuse of all these amazing resources (ie. dumping these materials in the landfill is a real ‘waste’, when they can be used for something else!).

Wow…ok, that ended up being WAY more of a tangent than I had intended!

Back to our regularly scheduled programming…

The point of my blathering is that I’ve learned that there doesn’t always need to be a ‘best’ strategy. In fact the best approach often involves combining multiple different approaches. I think this definitely applies in the case of composting/bokashi/vermicomposting, and I get the feeling JBB was onto the same idea by the time they sent me the second e-mail.

OK, with that brain dump out of the way, let’s now talk about each of these techniques in more detail, and see if we can’t at least come up with some sort of comparison for JBB’s benefit.

You can learn more about bokashi in my ‘Bokashi Basics‘ post, but let’s quickly review the process. Bokashi is a primarily anaerobic waste management technique that involves the use of a microbially-inoculated bran mixture (called bokashi), combined with a wide assortment of organic waste materials in some sort of sealed container (typically a bucket).

Vermicomposting (a.k.a. ‘worm composting’) is the breakdown of organic wastes via the joint action of earthworms (those specialized for the task) and microorganisms. It involves the setting up of some sort of ‘worm bin’ containing bedding and of course worms. Food wastes are added and the worms process them as they decompose (feeding primarily upon the microbes that have colonized the materials).

Odour free (if done properly – this can be a big “IF”, especially important to remember if you are just starting out)

Worms can be used for other things if you so please (food for other animals, fishing bait, sold for composting etc)

Like bokashi, vermicomposting is quite affordable, especially if you can get your worms for free

Ok, so as you can see both these methods have similar advantages, and both represent fun indoor strategies for dealing with kitchen (and other) wastes. In my case, I am looking forward to combining these methods (although I’ll certainly test out the garden-burial-method this summer as well) since I’m quite sure the ‘finished’ bokashi bucket with contain materials that the worms will be more than happy to process further.

The one and only downside that I see for bokashi, not encountered with worm composting, is that you basically do need some place to put the stuff. So, if you don’t have your own garden or sizable worm bin it may not be as practical for you. A worm bin on the other hand can literally go anywhere. Sure, your worms will eventually outgrow their home and you’ll need to separate out the castings (compost) at some point, but this is all still feasible for an apartment dweller.

Anyway, that is my (somewhat biased) bottom-line, in terms of a comparison of these two processes. I’m sure our friendly bokashi experts will chime in with their thoughts (hope so, anyway!).

Thanks again for the question, JBB! I thought this was just going to be a short little post, but you never can tell where a topic will lead you!

I came across a funny article (relating to composting) last night and of course couldn’t resist writing about it here on the blog. The article appeared in the Sunday Star Times (link to follow) back on December 16 and discusses a bizarre ruling made by the Aukland (New Zealand) Regional Council, relating to the health and well-being of composting worms.

Coll Bell, who invented the “wormorator” as an alternative to septic tanks, was told by an Auckland Regional Council staff member to get an expert’s report on the psychological impact on the worms after she became concerned during a site visit.

“She felt that the worms were being unfairly treated, being expected to deal with human faeces, and that it could affect them in a psychological way,” says Bell. “I said, `Well, what do I do about that?’ and she said `you have to have someone with the necessary qualifications to say the worms are happy’.”

In the wormorator, a colony of tiger worms, in a chamber, filters solids from the toilet waste. The leftover water is filtered and disposed of in underground trenches.

The ARC was satisfied after vermiculture consultant Patricia Naidu reported the worms were in excellent health and breeding happily.

Believe me, as a worm composting fanatic myself I certainly have a soft spot for the little wiggly guys, but C’MON – ‘psychological’ trauma??! That seems like a bit of a stretch to me. There are undoubtedly countless (newbie) home vermicomposters who have caused a lot more worms a lot more harm than this composting toilet system would. The fact is, if the system didn’t work, the worms would simply die.

As humorous as this article was, it also struck a chord with me – reminding me of this negative association people have with ‘waste’ materials – especially, it seems, when they come from our own body. People forget that all organic wastes can become a valuable resource for some other living organism, even if they seem ‘stinky and gross’ to us. Of course, that’s not to say that a composting toilet will always provide the ideal environment for vermicomposting, but chat more about the requirements shortly.

Using composting worms in compost toilet systems is certainly not a new invention (but regardless, I’m still very happy to see someone running with the idea). There are two full editions of the old Worm Digest (#8 & #9) dedicated to the topic. I was able to find an online article on the new site as well: The Worm Composting Toilet (scroll down to find it).

As with any worm composting system, if you provide with worms with enough high quality habitat before starting to add large amounts N-rich wastes (such as pee pee & doo doo) you should be ok. I’d recommend starting by setting up the composting toilet like a giant worm bin. Add lots of absorbent, carbon-rich bedding (such as shredded cardboard, peat or coir) mixed with some very well aged manure or food waste. Make sure the mix is well moistened and then let the system age for a little longer before adding the worms.
After the worms are added and the system is left alone for a little bit longer (to allow the worms time to get settled in) you can start using it as a composting toilet.

Aside from providing the worms with a safe zone to retreat into, it also would be very important to add ample amounts of carbon-rich bedding with each ‘deposit’ made into the toilet to kelp keep the system balanced.

Needless to say, whenever I read about someone using both vermicomposting and aquaponics as part of a larger integrated system, I get pretty excited!! Growing Power is an organization doing exactly that.

This non-profit organization, based in Milwaukee (with another location in Chicago), was founded in 1998 by Hope Finklestein – but the person most readily associated with Growing Power is Will Allen, a 6′ 7″ former pro-basketball player. After retiring from the American Basketball League and spending a number of years in the corporate world, Allen purchased (in the mid 90′s) a small piece of land zoned for agriculture within Milwaukee’s city limits – land that would eventually become the site for Growing Power.

Allen began growing crops on the land and started a non profit called Farm City Link. When Hope Finklestein toured the operation (shortly after founding Growing Power) and met Allen, the two quickly realized the similarity of their overall vision and decided to merge their efforts. Finkestein has since moved to Alaska, but remains very active in the organization.

Here is Growing Power’s Mission (as stated on the site):

Growing Power, Inc. is a non-profit organization and land trust supporting people from diverse backgrounds and the environment in which they live by helping to provide equal access to healthy, high-quality, safe and affordable food. This mission is implemented by providing hands-on training, on-the-ground demonstration, outreach and technical assistance through the development of Community Food Systems that help people grow, process, market and distribute food in a sustainable manner.

This is EXACTLY the type of organization I would love to get involved with!

The power source for the business is the second greenhouse, which holds the composting operation. Every week it welcomes 8,000 pounds of mash from an organic brewery, a thousand pounds of coffee grounds from local restaurants and tons of fruit and veggies that arrived at local food banks too late to be eaten. The process of composting throws off enough heat to keep the greenhouses warm through Milwaukee’s freezing winters.

And the way the compost is managed at Growing Power turns it into a money-maker. Huge bins made from scrap lumber are breeding grounds for tens of thousands of worms that break down the food scraps and produce castings that make top-grade fertilizer and compost every eight weeks.

“I couldn’t farm without these worms,” says Allen, a gentle giant of 6 feet, 7 inches, who refers to the little critters he holds lovingly in his oversized hands as his livestock. One bin of vermi-(worm)compost sells for $36,000 when wrapped into 2-ounce compost tea bags called Milwaukee Black Gold and sold to gardeners or in bulk to high-end growers. “It would take a rancher 300 steers to equal the value of my worm livestock,” he says.

His other livestock dominate the fourth greenhouse, where a 4,400-gallon fishing hole is alive with 4,000 tilapia, a small fish that evolved in Africa and Asia to withstand shallow, still waterways. The tilapia take eight months to reach their final weight, about a pound and a half, and live off algae, water lettuce, duckweed (39 per cent protein) and worms, all grown in the complex. When the tilapia do their business, they provide another business opportunity in another greenhouse, where the water with fish manure is mixed with compost tea to fill hydroponic canals and trays that feed a wide range of herbs and greens, including watercress, cilantro, basil, eddo and baby bok choy.

Some 5,000 pots of herbs grow in the enriched water, ready to be sent weekly to local chefs who lease their pots of herbs for $50 a month. “I can teach any group how to do this in a five-hour workshop,” says Allen.

This is an amazing model for urban agriculture – one that should be adopted in every major city as far as I’m concerned! Not only would it provide an incredible amount of additional healthy food, but it would help city dwellers to maintain a connection with with the earth. I’m hopeful that through the inspirational work of Growing Power and other similar organizations this can eventually become a reality!

As I mentioned in a recent article, I tend to lump hot (thermophilic) composting, vermicomposting, and (small-scale) ‘backyard’ composting together under the general term ‘composting’ (even though it is a term often referring to the thermophilic process). This of course is not to imply that they are all the same thing! They are in fact quite different.

In this article I will focus specifically on the difference between thermophilic composting and vermicomposting (composting with worms).

Let’s start by looking at the similarities.

Both of these processes involves the bio-oxidation of organic wastes – typically with human assistance – resulting in a rich, humus-like material. As ‘bio-oxidation’ implies, they both require oxygen for optimal performance.

The ‘carbon to nitrogen ratio’ (C:N ratio) is important for both, and plays an important role in determining the rate at which decomposition occurs – although it is definitely more important for hot composting.

That is essentially where the similarities end. Let’s now look at each process in more detail.

Hot Composting

As the name implies, thermophilic composting involves an important heating stage. This heat is caused by microbial metabolism and is dependent on the size of the heap, C:N ratio of the materials, moisture content and aeration. During this heating stage, temperatures will ideally be in the 140 F (60 C) range, but will often be higher or lower.

This type of composting typically follows the ‘batch’ model – that is to say all the materials for the heap are piled up at one time and no more is added. In order to establish a sustained heating phase a ‘critical mass’ of materials is required. Assuming adequate C:N ratio, a pile needs to be at least 1 cubic meter in size (somewhat larger is probably better though).

Hot composting can be achieved when materials in the pile have a C:N of between 20:1 and 40:1, but ideally it should be between 25:1 and 30:1.

Pros
1) Enables processing of larger quantities of materials in a smaller area
2) Can proceed relatively quickly under ideal conditions
3) Can kill weed seeds and pathogens
4) On a large scale can proceed easily in cold weather

Cons
1) Can be labor-intensive (piling wastes, turning pile etc) and require more attention
2) Heat can kill off many beneficial microbes
3) May require some stock-piling until sufficient materials available for ‘batch’
4) Heating can lead to considerable nitrogen loss

Vermicomposting

As mentioned, vermicomposting is somewhat similar to hot composting in that it involves the breakdown of organic wastes, but one of the major differences of course is that it involves the joint action of earthworms and microorganisms (whereas the other process relies solely on microbes). I should mention that the term ‘earthworm’ is actually somewhat misleading, since the worms needed for worm composting are specialized for life in rich organic materials (not soil).

Worm composting is also a much cooler process – working best at 59-86 F (15-30 C). It typically follows the ‘continuous’ composting model – that is to say materials are added continuously (usually in smaller amounts).

Again, C:N ratio while fairly important, is not quite so critical for optimal performance. Materials with high C:N ratios (such as paper sludge) have been processed quite readily via vermicomposting.

Pros
1) Tends to be somewhat less labor-intensive – no turning/aerating necessary (worm activity helps to mix, fragment and aerate materials)
2) Cooler temperatures help to conserve nitrogen
3) Higher moisture contents not an issue (and actually preferred)
4) Materials can be constantly added (no need to stock pile in preparation for next ‘batch’)
5) Size of system unimportant – ideally suited for both indoors and outdoors
6) Considerable academic evidence to indicate that vermicomposts have beneficial properties not found in hot composts
7) Under ideal conditions, wastes can be processed very quickly

Cons
1) Won’t kill seeds (and although there is a fair amount of evidence to indicate pathogen destruction, more research is required)
2) More space required to process similar amounts as hot composting – need to be careful with amount added (since excess heat will kill worms)
3) Outdoor systems much more limited by cold weather
4) Worms need to be separated from compost
5) Worms (although quite resilient) do require some attention and proper care.

As far as which of these two processes is “better”, it totally depends on the situation. I personally think an optimal approach (when possible) is to combine BOTH of these two methods. By ‘pre-composting’ then vermicomposting waste materials you can get the best of both worlds. Pathogen and weed seed destruction of hot composting (without too much nitrogen loss), followed by fast processing by worms and production of high quality vermicompost.

Needless to say, I’ll be talking about both these processes (along with other related composting methods) in much greater detail in coming weeks and months, so do stay tuned!

I wasn’t sure how I was going to kick things off. I tend to think about these sorts of things way too much, and and this was certainly no exception!

I decided in the end that the best approach was to simply write about a topic close to my heart – vermicomposting! I already have another site dedicated to the topic, but that certainly won’t stop me from providing plenty of wormy commentary and information over here as well!

My first inkling of an interest in worm composting actually can be traced back to my days as an avid aquarium hobbyist (something I’d like to get back to once I have a little more space!). Specifically, I was looking for various live foods I could easily raise at home, and worms seemed to offer great promise.

Like many other worm farming newbies, I naturally assumed I could dig up a bunch of worms from the garden put them in a bucket of soil with a little “food” and sit back while they bred like crazy! Of course it was only a matter of time before I ended up with a bucket of dead worms and an increased pessimism about the viability of home ‘worm farming’.

I finally clued in to the fact that I using the wrong kind of worms! What’s interesting is the fact that I had actually encountered a massive supply of red wigglers (composting worms) when I was working at a horse stable a number of years before. Out behind the barn there was a giant pile of old horse manure and it was absolutely jammed full of them.

I took a bucket full of them home with me, thinking I could start my own bait business. I even had the sense to dump them into a compost pile (a very dry, pathetic compost pile I might add), but it was hardly the ideal environment for them so they died off or at least vacated the area.

Everything finally came together for me a number of years later while working for an environmental consulting firm. One day I caught wind of the fact that a fellow co-worker kept a worm bin under her desk. I decided I have to see it for myself.

It was love at first sight!

Luckily my co-worker appreciated my sincere enthusiasm and offered to send me home with a decent number of red wigglers. I haven’t looked back since!

Well, I think that’s enough of a trip down memory lane for one post! You can expect to hear a lot more about worm composting here at Compost Guy (along with a wide variety of other topics), so stay tuned!